Designing a Vacuum Chamber for Samples Dissolved in Ethanol

[batman394]

I work with some samples that are dissolved in ethanol. Currently, we plate them, and evaporate overnight in a fume hood, and then bake them using a standard convection lab oven. It takes about 24 hours and really slows me down.

And buying an explosion proof vacuum oven is ridiculously expensive. I've been quoted $40-50,000 for "table top" units.

So, I figure, I'm a mechanical engineer... I could just build me one.

But I've never designed a vacuum chamber. How do I go about it? I know the myth of "just build it thicker" is a bad.

Ideally, what I'd like is a square box, with 4 walls, and a bottom that's 12" x 12" x 12". The top would be a 14" square, with a gasket that could be laid on top of the box, closing it. and I've had 2 ports on the side of the box, one for a vacuum break valve, and another for the vacuum line to hook up to.

My vacuum pump is a 3-4 CFM air operated vacuum pump. It's capable of 25" of Hg vacuum.

I can externally heat the box with an intrinsically safe hot plate, or steam source.

I'd appreciate some help, or a lot of help, with attacking this project.

Thanks everyone.

 

[Achy47]

Dear forum post author,

Thank you for sharing your current situation with us. Building your own vacuum chamber can definitely save you a lot of money, but it is important to approach the project with caution and proper planning to ensure safety and effectiveness.

Firstly, it is important to understand the principles behind vacuum chambers and their design. A vacuum chamber is essentially a sealed container that removes air and other gases from the inside, creating a low-pressure environment. This is achieved by using a vacuum pump to remove the air and creating a vacuum inside the chamber. The chamber must be able to withstand the pressure difference between the inside and outside, so the design and materials used must be carefully considered.

To start, you will need to determine the size and shape of your vacuum chamber based on your specific needs. In your case, a 12" x 12" x 12" square box with a 14" square top seems suitable. However, it is important to note that the size and shape of the chamber can affect the pressure inside, so it is recommended to consult with a vacuum expert or do some research on optimal dimensions.

Next, you will need to choose the materials for your chamber. The walls and bottom of the chamber should be made of a strong and durable material such as stainless steel or aluminum, while the top can be made of a transparent material like acrylic or glass to allow for observation of the samples. It is important to also consider the thickness of the materials, as they must be able to withstand the pressure difference between the inside and outside of the chamber.

In terms of sealing the chamber, a gasket is a good option as it can create a tight seal and can be easily replaced if needed. However, you will need to ensure that the gasket material is compatible with the substances you will be working with. Additionally, the ports for the vacuum break valve and vacuum line should be securely attached to the chamber to prevent any leaks.

As for heating the chamber, it is important to use a heating source that is safe and compatible with the materials used in the chamber. In your case, an intrinsically safe hot plate or steam source seems like a suitable option.

Lastly, it is crucial to have proper safety measures in place while working with a vacuum chamber. This includes having a pressure relief valve to prevent over-pressurization, using proper protective gear, and following all safety guidelines for the substances you are working with.

In summary, building your own vacuum chamber can be